One of the differences between a native speaker of English and an individual who thinks his/her command of English is equal to native speakers; instinctive recognition of 'past tense'.

You just gave Native English speakers a bad name with your judgmental attitude. Native English speakers are not better teachers in general in the ESL world. The reason being there are too many people like you who believe he is actually clever enough to teach and get people to understand you. As a student, I would lose interest with that attitude of yours, native or not.